.\" Copyright (c) 1990, 1991 The Regents of the University of California.
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.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek and the American National Standards Committee X3,
.\" on Information Processing Systems.
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.\"     @(#)fread.3	6.6 (Berkeley) 6/29/91
.\"
.\" Converted for Linux, Mon Nov 29 15:37:33 1993, faith@cs.unc.edu
.\" Sun Feb 19 21:26:54 1995 by faith, return values
.\" Modified Thu Apr 20 20:43:53 1995 by Jim Van Zandt <jrv@vanzandt.mv.com>
.\" Modified Fri May 17 10:21:51 1996 by Martin Schulze <joey@infodrom.north.de>
.\"
.TH FREAD 3  1996-05-17 "GNU" "Linux Programmer's Manual"
.SH NAME
fread, fwrite \- binary stream input/output
.SH SYNOPSIS
.nf
.B #include <stdio.h>
.sp
.BI "size_t fread(void *" ptr ", size_t " size ", size_t " nmemb \
", FILE *" stream );
.sp
.BI "size_t fwrite(const void *" ptr ", size_t " size ", size_t " nmemb ,
.BI "              FILE *" stream );
.fi
.SH DESCRIPTION
The function
.BR fread ()
reads
.I nmemb
elements of data, each
.I size
bytes long, from the stream pointed to by
.IR stream ,
storing them at the location given by
.IR ptr .
.PP
The function
.BR fwrite ()
writes
.I nmemb
elements of data, each
.I size
bytes long, to the stream pointed to by
.IR stream ,
obtaining them from the location given by
.IR ptr .
.PP
For non-locking counterparts, see
.BR unlocked_stdio (3).
.SH "RETURN VALUE"
.BR fread ()
and
.BR fwrite ()
return the number of items successfully read or written (i.e., not the
number of characters).
If an error occurs, or the end-of-file is
reached, the return value is a short item count (or zero).
.PP
.BR fread ()
does not distinguish between end-of-file and error, and callers must use
.BR feof (3)
and
.BR ferror (3)
to determine which occurred.
.SH "CONFORMING TO"
C89, POSIX.1-2001.
.SH "SEE ALSO"
.BR read (2),
.BR write (2),
.BR feof (3),
.BR ferror (3),
.BR unlocked_stdio (3)
.SH COLOPHON
This page is part of release 3.22 of the Linux
.I man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
